Effect of Droplet Size and Nitrogen Rate on Protein Content of Hard Red Winter

Wheat (Triticum aestivum L.)

Ethan WyattPlant and Soil Sciences

Oklahoma State University

Introduction The United States ranks fourth

in global wheat production.

In the United States more than 21 million hectares of wheat is produced each year.

Hard red winter wheat (HRWW) is grown extensively in the Great Plains region which accounts for 40% of the total wheat grown in the U.S.

iwheat.org, 2013

In recent years hard red winter wheat protein levels have been a concern with milling and baking companies.

Grain protein concentration (GPC) levels determine the degree of milling and baking quality of processed wheat products and price

As of November 30, 2010, marketable grades of HRWW must contain a protein level of at least 11% or a 10 cent dockage to the contract price with a protein level of 10.5% (KCBT, 2010)

Agronomic Problem

Grain protein levels are variable across locations due to environmental and genetic factors (Kramer, 1978)

Rao et al., (1993) GPC is controlled by many different aspects including environment, cultivar, nitrogen fertilizer rate and timing

Research on late-season top-dress N as either dry or liquid material has shown an increase in GPC (Woodward and Bly, 2003)

Woolfolk et al., (2002) GPC was increased with late season foliar N before and following flowering

According to Mercer (2007) decreasing droplet size increased uptake of the active ingredient and increased the spread area of the droplet which increased uptake of the active ingredient

Review of Literature

To evaluate the effects of adjuvant, droplet size, and foliar N rate on wheat grain protein and yield

Objective

Methodology

Treatment

Foliar N (kg N ha-

1)

Droplet size Nozzle PSI MPH

1 0 — — — —2 11.2 Fine, with adjuvant FC- TR110-

01525 5

3 11.2 Medium, with adjuvant

GRD120-01 60 5

4 11.2 Coarse, with adjuvant

GRD120-015 25 5

5 11.2 Fine FC- TR110-015

25 5

6 11.2 Medium GRD 120-01 60 57 11.2 Coarse GRD 120-015 25 58 22.4 Fine FC-TR110-02 60 59 22.4 Medium GRD120-02 60 5

10 22.4 Coarse GRD120-02 40 4

Efaw, Stillwater, OK, Perkins, OK, and Lake Carl Blackwell Randomized complete block design (RCBD), 3 reps

Foliar N applications were applied immediately following anthesis.

Alleys included in the design so foliar N application could be applied without damaging plots with the ATV applicator

Methodology

Experimental design and treatment layout for the Lake Carl Blackwell experiment

Gary James at HYPRO Global Spray Solutions provided spray tips and technical support

Three to five days following application 15 flag leaves were chosen at random throughout each plot

At harvest, grain yield and subsamples of the grain were collected from each plot.

Grain and flag leaf samples were processed and analyzed for total N using a LECO Truspec CN dry combustion analyzer

Grain protein % and N uptake were calculated by:

Methodology

Massey Ferguson 8XP combine used to harvest plots. Combine has subsampling and yield recording capabilities

Results

Trt. 5 Trt. 2

Differences visible showing awn burn from the foliar N*adjuvant treatments in 2012

Foliar N burn was more frequent in all treatments in 2013. Left, visual burn signs of foliar N application compared to the right which was the check.

Yield

0 11.2 11.2 11.2 22.4 22.4 22.4Check C M F C M F

3700

3800

3900

4000

4100

4200

4300

4400

Yield

Foliar N Rate (kg N ha-1) and Droplet Size

Yie

ld k

g h

a-1 e e

e

dbc

a ab

Treatment comparisons for grain yield as influenced by droplet size and foliar N rate, LCB, OK, 2013

Check

10 FA

10 MA

10 CA

10 F 10 M

10 C 20 F 20 M

20 C0

500

1000

1500

2000

2500

Yield

Treatment

Yiel

d kg

ha-

1

abc

f

ab

def

a

bcd

def

bcde

defcdef

Grain yield by treatment at LCB, OK, 2012. Relationship of grain yield and foliar N rate at Perkins, OK, 2013.

Relationship of yield and nitrogen uptake with droplet size (coarse, medium, fine) LCB, OK, 2012.

Grain ProteinTreatment means for grain protein with mean separation at Lake Carl Blackwell, 2013. Foliar N kg ha-1 Droplet Size Adjuvant Protein %

0 None No 12.65 g 11.2 Fine Yes 14.70 a 11.2 Medium Yes 14.40 ab 11.2 Coarse Yes 14.30 abc 11.2 Fine No 14.00 abcdef 11.2 Medium No 13.44 bcdefg 11.2 Coarse No 13.61 abcdefg 22.4 Fine No 14.25 abcd 22.4 Medium No 14.14 abcde 22.4 Coarse No 13.20 cdefg

LSD.05 1.11

a denotes significant differences in means, LSD.05

Relationship between grain protein and foliar N rate, Efaw, OK, 2012.

Check vs foliar N, 1 vs 2-10, single degree of freedom contrast LCB, OK, 2013.

Non-adjuvant vs adjuvant, 2,3,4 vs 5,6,7, single degree of freedom contrast, LCB, OK, 2013.

Overall Protein

Yield differences observed were relatively small across locations and years

For most locations and years GPC was increased linearly with higher rates of foliar N applied

When compared to the check, late season foliar N application can improve grain protein by up to 2.0%

Use of the fine droplet size with a foliar N rate of 11.2 kg N ha -1 with an addition of an adjuvant resulted in the highest GPC

This work suggests that more emphasis should be placed on protein prediction and improving mechanisms to improve late season foliar N uptake

Conclusions

Late season foliar N to improve protein levels should be applied to:◦ Growing wheat under high yielding production systems

Irrigation production systems High rainfall areas/years

◦ Growing wheat with less than optimum nitrogen requirement applied

Late season foliar N application should be applied when:◦ Crop is healthy◦ Temperature is below 65 degrees F◦ Low humidity ◦ Low wind days

Producer Recommendations

Funding, Soil Fertility Research and Education Advisory Board

Spray nozzles and droplet size technical support was provided by Gary James at HYPRO

Foliar N applicator built by Dr. Randy Taylor, BAE

Committee Members: Dr. Raun, Dr. Arnall, Dr. Taylor

PASS graduate students

Acknowledgements

Questions?